1. Field of the Invention
The present invention relates to a semiconductor chip having an island dispersion structure on the back surface of the semiconductor silicon substrate and a method for manufacturing the same.
2. Description of the Related Art
When a semiconductor silicon wafer is manufactured or worked on, there is sometimes a porous silicon layer deposited on the semiconductor silicon wafer.
As this porous silicon layer may get in the way of jointing of a plug in setting up the plug in a semiconductor chip obtained from the semiconductor silicon wafer, the porous silicon layer is removed during manufacturing and working on of the semiconductor silicon wafer. For this reason, the semiconductor chip usually has no porous single-crystal layer (See Japanese Patent Application Publication No. H10-335632).
However, for a semiconductor chip of extremely limited application, for example, photodiode, there is proposed a semiconductor chip having a porous silicon layer. This porous silicon layer has a property of converting light of short wavelength into visible light. In order to make effective use of this property, as an essential requirement for configuration the porous silicon layer is provided on the same side of the semiconductor chip as a semiconductor device layer (See Japanese Patent Application Publication No. 2004-214598).